a real challange?

[Penthode]

About nearly 20 years ago I bought on eBay an HP 8601a sweep generator and it's companion HP 8600 frequency counter. It covers a frequency range of 100kHz to 120MHz and is ideal for performing accurate sweep alignment of a wide range of devices. It provides up to six markers that are very accurate.

I bought the HP8601a for $34 and the HP8600 for $45. I see that they are more now on eBay. (I wonder if these actually sell?) I negotiated with the sellers years ago for a better price.

I suppose the point here is that there is a variety of more sophisticated alignment setups available at a reasonable price. I have been gratwful acquiring decent test equipment as I can align easily and with confidence any TV.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Did you adjust the 1st IF per the alignment instructions using your new rf generator, or was that a best visual tweak attempt? You are still using the test CRT in that last video? It almost looks like outside interference.

reading this in another thread reminded me


Quote:
Originally Posted by vortalexfan View Post
So does flaky dag coating cause the symptoms I had previously described like I was thinking it was or is the flickering, bouncing screen symptoms a symptom of something else wrong with the TV?
Just curious.
Yes indeed. It can cause symptoms out the wazoo mimicking sync, AGC and tuner erraticies galore.

if you look close

https://imgur.com/BjSCvw5

there is NONE
could that be part of the problem?
:O
there SHOULD be some.

[bandersen]

Assuming your set has a doorknob HV filter cap, the dag isn't going to make any difference. It's not there for shielding, it's there to form a filter cap for the HV for sets that didn't use a separate HV filter.

Notice the shiny inside of the CRT ? That's a metal coating on the inside connected to the HV. It also acts as a shield from interference.

[Electronic M]

Some test CRTs are purpose built without dag because they are different sized than the original...The dag ground spring on the chassis probably won't touch it. If the spring isn't touching it the dag goes from a filter cap to a floating HV source for nasty static jolts and possibly a noise source.

When dag isn't grounded it tries to arc to ground and or put out Corona (the static to air discharge, not the beer, the virus or the mythical beer-virus ) both of which create electrical noise that can disrupt the set....it is worse when the dag is flaking creating dag islands or the ground spring contact point dag is the damage point because floating conductors at different potentials in close proximity make stronger more frequent arcs than distant ones.

[Yamamaya42]

well if there is some kind of "external interference" making the video look crappy, I don't know what it is, other than my PCs perhaps or what to do about it.
The new generator will be here tomorrow, and will try to adjust 1st IF again over the weekend.

[Electronic M]

Is the HV cage cover, tube shields and any other factory shielding all properly in place as far as you can tell? Sometimes when a shield is missing it causes issues.

It probably won't make any difference but if you're bored and want to see if a CRT with dag stops the noise you could always put the set upright slip the original CRT in and put a piece of wood or styrofoam, or something under the screen to support it and give it a run that way...

[Yamamaya42]

No, as of now, the HV cage cover is not put back on yet...
Did not think of that.
I still have an annoying problem in there that is not fully fixed yet, the clip for the doorknob cap C103 has a tab broken off, and hardly stays in place, I was thinking of using some shrink wrap to keep it there, just have not done it yet.

[Kevin Kuehn]

Originally Posted by Yamamaya42

No, as of now, the HV cage cover is not put back on yet...
Did not think of that.
I still have an annoying problem in there that is not fully fixed yet, the clip for the doorknob cap C103 has a tab broken off, and hardly stays in place, I was thinking of using some shrink wrap to keep it there, just have not done it yet.

Can you not solder directly the wire to the cap post? Sounds like you've got some cleanup work to do before worrying about interference.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Can you not solder directly the wire to the cap post? Sounds like you've got some cleanup work to do before worrying about interference.

it's not really the solder type of cap.

you can see it clearly in this guy's thread of the 630ts

https://antiqueradio.org/art/RCA630TS20.jpg
https://antiqueradio.org/art/RCA630TS19.jpg

my clip broke, but will almost stay in place.

I also found this interesting from his article.

https://antiqueradio.org/RCA630TSTelevision.htm

"In addition to paper capacitors, I replaced four 270pf mica capacitors (C116, C123, C128, and C134) which serve as coupling capacitors in the picture IF section. Mica capacitors are usually more reliable than paper ones, but an experienced TV restorer told me that these can be troublesome, so out they went. "

gonna do that too...

[Yamamaya42]

OK.

closing the HV cage made no dif :/


the fix on the clip I mentioned.
https://imgur.com/bF0VRRu
before

https://imgur.com/4Tm30KZ
after.


it holds it in place well enough.

I did find that changing from chan 3 to 4 on the RF mod i was using did help things :O

https://www.youtube.com/watch?v=FANp...ature=youtu.be

still not sure about the smear yet

[Yamamaya42]

still finding some crappy resistors.
R52 (820k 5%) checked @ 930k and R55 (3.3k 10%) checked @ 4.6k.
not sure if that is the cause of the video smear yet, but will keep looking as I try to adjust 1st IF again.

[Kevin Kuehn]

Originally Posted by Yamamaya42

I did find that changing from chan 3 to 4 on the RF mod i was using did help things :O

https://www.youtube.com/watch?v=FANp...ature=youtu.be

still not sure about the smear yet

That looks a lot better. So definetly you were/are picking up some external interference. If you haven't already, try turning off all lights, computers, and any wall wart power supplies in the house. Almost all newer florescent and led fixtures and most power supplies emit wide band rf noise. Whenever I'm working with a TV or radio in my basement I have all things turned off except my old school magnetic ballast florescent lights above my workbench.

I don't think any resistors would be causing picture smear, that's most likely a tuning, noise, or alignment issue. Have you tested all of the video peaking coils for continuity?

[Kevin Kuehn]

Watching that video a second time, it almost looks like there are dark trails behind light objects, which could be from too high of brightness and/or contrast for the tired old CRT. Try taming that picture down and see if that helps. Or maybe it's just the camera making it look that way to me. Without seeing it up close it's kind of hard to distinguish what it really looks like. Possibly some other programming could create a more distinct picture? Overall that channel change made a real big improvement.

[edit] Just realize that's your test crt we're still watching. That in itself could be responsible for some of that tailing.

[Yamamaya42]

EICO came today as expected,
https://imgur.com/kaKymuU

and after a brief upgrade

replaced the paper caps ( that mattered , they were WAY off, ) the electrolytics , and replaced the selenium rectifier.


also cleaned all pots and switches.
https://imgur.com/UXStu5t

it's now VERY stable!

[Yamamaya42]

https://imgur.com/a/Y7sBu6J

all set to try again!